Abstract: A reversible closure system for containers is disclosed. A cap is adapted as a closure that may be reversibly affixed to a container in either a child-resistant configuration or a non-child resistant configuration. An upper portion of the cap is adapted to function in a non-child resistant closure mode, and a lower portion of the cap adapted to function in a child-resistant closure mode. The upper portion of the cap functions in a non-child resistant configuration to secure the cap to the container by inserted engagement of a cylindrical plug section having a side wall provided with threads that mate with corresponding threads on the inner surface of the mouth of the container. An outer skirt is disposed in surrounding relation with the plug section to shield and protect the threads from damage.